There are not a lot of cards that helps with reducing a units defence and this seems to be a good option.

Comparing to corruption, they both "disable" a unit in someway while making defense = 0.

Corruption makes it easy to kill while the 2 agi makes sure their action won't be fast but allows them to pull off their Start Skills with possibility of going that turn still.

Dire Straights is a jack of all trades situational card, useful if you need to make defense 0 or engage. It is 1 more sp than Soul Bind but it pays for itself by reducing the opponents sphere levels by 1.

For example, it's kind of a tossup on which one I will use on Verlaat. Corruption makes it easy to kill him but his start skill will boost the rest of their field. Dire straights will make sure his start skill doesn't go but still have to hit him for 65hp. The sphere level drop might help depending on the part of the game you're in.

the sphere drain is massive for multisphere, which a lot of people do nowadays, esp the top players... it's why the stronghold had to get nerfed, and even when you encounter it turn 3, you still say FFFFFFFFFFFFFFF that!

the engage and debuff means that the target unit will prolly die or die next turn. usually you use this on a Bringer. of course dire straits will be kinda useless against a rush level 3 file, but against mids, this nasty grim does crazy stuff.